A 2.5-D Integrated Data Logger for Measuring Extreme Accelerations

Abstract

A very compact and rugged 2.5-D integrated data logger has been built and tested. The data logger is capable of measuring accelerations exceeding 70 000 g. Microcontroller and flash memory as bare dies have been mounted onto a silicon interposer with through silicon vias using anisotropic conductive film and Au stud bump bonding. A microelectromechanical system accelerometer is mounted onto the interposer, using a robust customized flip-chip mounting approach. The interposer is mounted into a 16-pin leadless chip carrier package using isotropic conductive adhesive, where the conductive part is made of metallized polymer spheres. The ceramic package was mounted onto an application printed circuit board (PCB) with filters, power management, and an interface contact, using soldered plastic core solder balls (PCSBs). The diameter of the data logger is less than 9 mm, and the height is approximately 5 mm. The data logger fits within 12.7-mm (0.50 cal.) projectile, and acceleration measurements have been performed during firing, flight, and recovery. The measured accelerations have been verified by comparing the calculated projectile muzzle velocities with Doppler radar measurements.